Scientists believe that the Chatham Rise is New Zealand's only known juvenile hoki nursery. Photo / APN

What's good for the environment is good for business. Those of us in the fishing industry know that better than anyone. Without enough fish, we wouldn't have an industry. Our success depends on our ability to grow our business while protecting the source of that growth.

Last year hoki fishing made $195 million in export earnings. I'm proud of the value that adds to the New Zealand economy, and the number of local jobs it reflects. Development is good for New Zealand. I'm not anti-mining. But I am deeply concerned about a proposal before the courts to mine the protected seabed of the deep waters off the Chatham Islands.

Chatham Rock Phosphate are lodging a proposal with the Environment Protection Authority this week to mine for phosphate (for use in fertilisers) by vacuuming up large tracts of the Chatham Rise seabed, extracting the phosphate and returning the debris to the sea.

Scientists believe the Chatham Rise is the location of the only known juvenile nursery for hoki in New Zealand.

It seems that all young hoki migrate from the spawning grounds (off the West Coast of the South Island and the Cook Strait) to the Chatham Rise. Once the fish are bigger, they migrate off again to other areas.

Interfering with this nursery could devastate the entire hoki fishery and cost the country millions of dollars. We simply don't know enough to allow this to happen. Not only that, seabed mining at this depth has never been done before. Risking an entire fishing industry to experiment with untested techniques and for limited economic gains makes no sense. Imagine finding out in 10 years' time that we'd decimated the hoki stocks?

Chatham Rock Phosphate agree that everything in the direct line of the drills will be killed. What no one knows is the long-term effect of dumping the dirty cloud of debris back into the sea after the phosphate has been extracted.

The risk to other fish stocks and marine life is even greater because Chatham Rise is in an underwater "national park" - a Benthic Protection Area (BPA).

In 2007 the fishing industry persuaded the Government to "fence off" 1.1 million sq km of our seabeds to prevent any bottom trawling or dredging in these "parks". We protect these areas for a reason. They represent a full range of marine seabed habitats and ecosystems, and protecting this helps us secure a sustainable seafood industry.

If you do the maths, the potential damage to the seabed in this "national park" is staggering. The drills will vacuum up the equivalent of a small mountain like Mt Victoria in Wellington every day that the mining vessel is on-site - for 15 years.

By the end of that, the Chatham Rise mine site will be 20 times bigger than New Zealand's largest open cast coal mine (the Stockton mine on the West Coast of the South Island) and 250 times bigger than the proposed new Escarpment open cast coal mine on the Denniston Plateau.

The area affected would be nearly three times as big as the Auckland Harbour.

Today there are 17 BPAs and 19 protected seamounts within New Zealand's Exclusive Economic Zone. That means 30 per cent of the zone is now protected from dredging and trawling.

It makes a mockery of our attempts to protect these seabeds if we are about to allow a mining company to rip them up using untested techniques, with no guarantee that any economic benefits will stay in New Zealand, and no certainty that the fish stocks won't be damaged.

And unlike any proposed mining in our national parks on land, this will happen 400m under the sea where we can't scrutinise it.

I hope the Environment Protection Authority will see sense and say unless we have better baseline monitoring and research that tells us this is safe, it's not worth risking a New Zealand industry that produces seafood for more than one billion meals each year around the world.